A time zone is a geographical region in which the same standard time is used.

Important Note:

Whenever possible, use the TimeZoneInfo class instead of the TimeZone class.

You can use the TimeZone class to retrieve information about the current time zone, and to convert times from local time to Coordinated Universal Time (UTC) or vice versa. However, you cannot use the TimeZone class to represent time zones other than the local zone or to handle date and time conversions from one time zone to another. For this purpose, use the TimeZoneInfo class. You can use this class to retrieve information on any time zone defined on the local system, to create custom time zones, and to convert times from one time zone to another.

The TimeZone class supports only a single daylight saving time adjustment rule for the local time zone. As a result, the TimeZone class can accurately report daylight saving time information or convert between UTC and local time only for the period in which the latest adjustment rule is in effect. In contrast, the TimeZoneInfo class supports multiple adjustment rules, which makes it possible to work with historic time zone data.

Notes to Inheritors:

In addition to providing implementations for its abstract members (those marked MustOverride in Visual Basic), it is important that classes derived from TimeZone override the default behavior of the ToLocalTime method. This is because the default behavior of ToLocalTime in the .NET Framework version 2.0 does not depend on a call to GetUtcOffset, as it did in the .NET Framework versions 1.0 and 1.1. For details, see the ToLocalTime method.